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Commit Graph

4 Commits

Author SHA1 Message Date
Volker Lendecke
c9cced0322 poll_funcs_tevent: Fix a valgrind error
The valgrind error happened in poll_funcs_tevent_handle_destructor in

  if (handle->ctx->refcount == 0)

handle->ctx was already gone at the time this destructor
was called. It happened because during messaging_init the
messaging_dgm subsystem was free'ed.  The unix_msg context and the
poll_funcs_tevent_context are children of messaging_dgm_context. How
was poll_funcs_tevent_handle_destructor still called? While working
on the new notify subsystem I've added some messaging_read_send
tevent_reqs, which register themselves with the dgm_context via
messaging_dgm_register_tevent_context. They were not gone yet. When
later these were also run down due to another talloc_free somewhere else,
this destructor referenced dead memory.

This code now protects the poll_funcs_tevent_handle against the
poll_funcs_tevent_context going away first with the loop

       for (h = ctx->handles; h != NULL; h = h->next) {
               h->ctx = NULL;
       }

in poll_funcs_tevent_context_destructor together with

       if (handle->ctx == NULL) {
               return 0;
       }

in poll_funcs_tevent_handle_destructor.

A side-effect of this code is that messaging_read_send request won't be
satisfied anymore after a reinit_after_fork kicked in. But I think this is the
right thing anyway: Every process should register its own message handlers
explicitly.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2014-10-24 01:40:16 +02:00
Volker Lendecke
dca572ff1c lib: Enhance poll_funcs_tevent for multiple tevent_contexts
With this patch it will be possible to use nested event contexts with
messaging_filtered_read_send/recv. Before this patchset only the one and only
event context a messaging_context is initialized with is able to receive
datagrams from the unix domain socket. So if you want to code a synchronous
RPC-like operation using a nested event context, you will not see the reply,
because the nested event context does not have the required tevent_fd's.
Unfortunately, this patchset has to add some advanced array voodoo. The idea
is that state->watches[] contains what we hand out with watch_new, and
state->contexts contains references to the tevent_contexts. For every watch we
need a tevent_fd in every event context, and the routines make sure that the
arrays are properly maintained.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2014-05-08 09:10:12 +02:00
Volker Lendecke
2995b93440 poll_funcs: Fix a comment typo
Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: David Disseldorp <ddiss@samba.org>

Autobuild-User(master): David Disseldorp <ddiss@samba.org>
Autobuild-Date(master): Sun May  4 22:19:53 CEST 2014 on sn-devel-104
2014-05-04 22:19:53 +02:00
Volker Lendecke
bafdecdf1f lib: Add poll_funcs
This is an abstraction for a tevent loop. It will be used in low-level
messaging with the goal to make low-leve our low-level messaging routines
usable also for other projects which are not based on tevent.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2014-04-23 22:33:08 +02:00